Well, it seems to me that Bernard would have to know Octavius on some level, even if it is a simple constituent-leader relationship. And obviously he would know Maxine, who knows him only as her sire.

Other than that, looks like most of the characters could reasonably know [i]of[/i] Bernard, but he hasn't been very active for the past two centuries or so. I'm going to read and think more to try and connect some specifics, but in the mean time I'm here if anyone wants to discuss this.